Vegetable lipid-based composition and candle

ABSTRACT

A vegetable lipid-based composition and candle comprised of a vegetable lipid component and a petroleum wax is described. The vegetable lipid component may include a triglyceride or a free fatty acid/triglyceride mixture. The vegetable lipid-based composition has properties that make it advantageous in candle production.

RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/223,411filed Aug. 19, 2002, which is a continuation of application Ser. No.09/802,137, filed Mar. 8, 2001, now U.S. Pat. No. 6,497,735, which is acontinuation of application Ser. No. 09/132,991, filed Aug. 12, 1998,now U.S. Pat. No. 6,284,007.

BACKGROUND OF THE INVENTION

This invention relates to vegetable lipid-based compositions that areadvantageous to candle production. More specifically, the inventionrelates to a vegetable-lipid based composition including a vegetablelipid component and a petroleum wax wherein the composition contains agreater concentration of the vegetable lipid component than thepetroleum wax. The vegetable lipid component includes either atriglyceride or a free fatty acid/triglyceride mixture.

Candles have long been used for light as well as for ceremonies andrituals. These candles are typically manufactured from compositionscontaining solid animal fats and waxes. Suitable waxes include petroleumwaxes such as medium paraffin wax and microcrystalline paraffin wax thatare derived from petroleum refining processes. The petroleum waxcomponent of these candles is usually present in greater amounts thanthe solid animal fats.

Candles made from petroleum waxes produce a black smoke upon burning andgenerally exhibit an unpleasant odor. The black smoke of petroleum-basedcandles contains polycyclic aromatic hydrocarbons, metals, and sulfurcompounds that may be carcinogenic and/or toxic. Burning these candlesin an enclosed environment increases the concentrations of thesecompounds and could therefore increase the detrimental effects that theymay have.

Moreover, the cost of the petroleum wax will likely increase due to itslow supply and increasing demand. Petroleum refining processes areconstantly being improved to maximize quantities of short chainhydrocarbons and aromatic chemicals and the production of petroleumwaxes is being reduced.

In this regard, candles are known that contain greater amounts of butteroil than conventional candles; however, compositions used to make thesecandles typically contain other ingredients, such as emulsifiers. Theseextra ingredients add to the complexity of the mixture and generallyincrease the cost of the candle.

As a result, there is a need for a candle composition that minimizes therisk to human health upon burning, utilizes renewable resources whileminimizing or eliminating use of petrochemical-derived products, and hasa naturally pleasing odor that does not require additional fragrances.This invention addresses that need.

SUMMARY OF THE INVENTION

The present invention provides a vegetable lipid-based compositionhaving properties advantageous for candle production. The vegetablelipid-based composition includes a vegetable lipid component and apetroleum wax. The vegetable lipid component may be a triglyceride or afree fatty acid/triglcyeride mixture. The composition preferablyincludes a greater concentration of the triglyceride or free fattyacid/triglyceride mixture than the petroleum wax.

In one preferred embodiment, the vegetable lipid-based compositionincludes about 51% by weight to about 100% by weight of the triglycerideor fatty acid/triglyceride mixture and up to about 49% by weight of thepetroleum wax, wherein the free fatty acid/triglyceride mixture includesabout 1% by weight to about 99% by weight of the free fatty acid andabout 1% by weight to about 99% by weight of the triglyceride. Thepetroleum wax may include a medium paraffin wax, a microcrystallineparaffin wax or a petroleum wax obtained from crude oil refined to otherdegrees.

In another embodiment, the vegetable lipid-based composition includesabout 83% by weight to about 100% by weight of the triglyceride or thefatty acid/triglyceride mixture and up to about 17% by weight of thepetroleum wax, wherein the fatty acid/triglyceride mixture includesabout 1% by weight to about 99% by weight of the free fatty acid andabout 1% by weight to about 99% by weight of the triglyceride.

In yet another embodiment, the vegetable lipid composition includes onlythe vegetable lipid component and the petroleum wax. In otherembodiments, other components may be added to the composition, includingcolorants and odorants.

The present invention also provides a candle formed from the vegetablelipid-based compositions.

Accordingly, one object of the invention is to provide a vegetablelipid-based composition, and candles produced with such compositionsthat, when burned, minimizes the risk to human health, utilizesrenewable resources, minimizes or eliminates the use ofpetrochemical-derived products and has a naturally pleasing odor.

Other objects and advantages of the present invention will be apparentafter reading the following description.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purpose of promoting an understanding of the principles of theinvention, reference will now be made to certain embodiments thereof andspecific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations, modifications andfurther applications of the principles of the invention illustratedherein being contemplated as would normally occur to one skilled in theart to which the invention relates.

The present invention provides a vegetable lipid-based composition and acandle formed therefrom. The composition includes a vegetable lipidcomponent, including a triglyceride or a free fatty acid/triglyceridemixture, and a petroleum wax. The vegetable lipid component of thecomposition is preferably present in the composition in a greaterconcentration by weight than the petroleum wax component.

As known in the art, triglycerides are fatty acid esters of glycerol. Asused herein, the term “free fatty acid” will refer to a fatty acid thatis not covalently bound through an ester linkage to glycerol.Additionally, as used herein, the term “fatty acid component” will beused to describe a fatty acid that is covalently bound through an esterlinkage to glycerol.

The triglycerides and free fatty acids are obtained preferably fromplant sources, including soybean, cottonseed, corn, sunflower, canolaand palm oils. The triglycerides are used after normal refiningprocessing by methods known in the art. For example, plant triglyceridesmay be obtained by solvent extraction of plant biomass using aliphaticsolvents. Subsequent additional purification may involve distillation,fractional crystallization, degumming, bleaching and steam stripping.The triglycerides are also partially or fully hydrogenated. Furthermore,fatty acids may be obtained by hydrolysis of natural triglycerides(e.g., alkaline hydrolysis followed by purification methods known in theart, including distillation and steam stripping) or by synthesis frompetrochemical fatty alcohols. The free fatty acids and triglycerides mayfurther be obtained from commercial sources, including Cargill, ArcherDaniels Midlands and Central Soya.

The free fatty acids and fatty acid components of the triglycerides arepreferably saturated and their chains exhibit varying length. However,the free fatty acids and fatty acid components of the triglycerides maybe unsaturated as long as the final candle composition will be a solidat the temperature at which the candle is used. The properties of thefree fatty acid/triglyceride mixture, such as melting point, will varyas a function of the chain length and degree of saturation of the freefatty acids and the fatty acid components of the triglycerides. Forexample, as the degree of saturation decreases, the melting pointdecreases. Similarly, as the chain length of the fatty acids decreases,the melting point decreases. Preferred free fatty acids are thesaturated fatty acids such as palmitic acid and include saturated fattyacids of longer carbon chain length, such as arachidic acid and behenicacid. Stearic acid is further preferred.

Table 1 depicts the preferred fatty acid components of the triglyceridesin the present invention along with their preferred maximum percentagesby weight. TABLE 1 Fatty Acid Composition Ranges of Triglycerides inVegetable Lipid-Based Compositions Fatty Acid Chain Length* WeightPercent 12:0 0.21 14:0 0.77 16:0 39.28 18:0 74.22 20:0 0.19 22:0 0.06416:1 0.28 18:1 72.82 20:1 1.035 18:2 33.91 18:3 4.97*number of carbon atoms:number of double bonds (e.g., 18:2 refers tolinoleic acid)

As seen in Table 1, when unsaturated, the fatty acid componentspreferably contain about 1 to about 3 double bonds. The preferred chainlength of the fatty acid components ranges from about 12 to about 22carbon atoms. The preferred fatty acid components of the triglyceridesinclude palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1),arachidic acid (20:0) and behenic acid (22:0). For example, in oneembodiment of the invention as seen in Table 1, the triglyceridecomponent of the composition preferably contains up to about 74% byweight of the 18 carbon, saturated fatty acid component stearic acid. Inanother embodiment, the triglyceride preferably contains up to about 73%of the monounsaturated 18 carbon fatty acid component oleic acid. In yeta further embodiment, the triglyceride contains up to about 39% of thefatty acid component palmitic acid.

The vegetable lipid-based composition may include about 51% by weight toabout 100% by weight of the vegetable lipid component including a freefatty acid/triglyceride mixture with the remainder including petroleumwax. Moreover, the vegetable lipid component may include only atriglyceride. However, the vegetable lipid-based composition preferablyincludes about 55% to about 100%, about 65% to about 100%, about 75% toabout 100% and, more preferably, about 83% by weight to about 100% byweight of the vegetable lipid component. The free fattyacid/triglyceride mixture includes, on a weight percentage basis, about1% to about 99% of the free fatty acid and about 1% to about 99% of thetriglyceride but preferably includes about 1% to about 75% of the freefatty acid and about 25% to about 99% of the triglcyeride, about 1% toabout 50% of the free fatty acid and about 50% to about 99% of thetriglyceride, and about 1% to about 25% of the free fatty acid and about75% to about 99% of the triglyceride. Further preferred free fattyacid/triglyceride mixtures include about 5% to about 95% of the freefatty acid and about 5% to about 95% of the triglyceride, about 5% toabout 75% of the free fatty acid and about 25% to about 95% of thetriglcyeride, about 5% to about 50% of the free fatty acid and about 50%to about 95% of the triglyceride, and about 5% to about 25% of the freefatty acid and about 75% to about 95% of the triglyceride. Even morespecifically, superior candle quality may also be achieved when the freefatty acid/triglyceride mixture includes at least about 5% free fattyacids and about 95% triglycerides. For example, a preferred vegetablelipid composition includes about 5% by weight stearic acid and 95% byweight triglycerides having the following fatty acid components: about17.2% palmitic acid, about 38.4% stearic acid and about 44.4% oleicacid, all on a weight-percent basis.

The petroleum wax of the present invention is a by-product of thepetroleum refining process and may be obtained commercially fromsuppliers such as Witco. The quality and quantity of the wax obtainedfrom the refining process is dependent upon the source of the crude oiland the extent of the refining. The petroleum wax component of thevegetable lipid-based candle composition includes, for example, aparaffin wax, including medium paraffin wax, microcrystalline paraffinwax or a combination thereof However, petroleum wax obtained from crudeoil refined to other degrees may also be used in the invention.

Although the exact chemical compositions of these waxes are not known asthe nature of these by-products vary from one distillation process tothe next, these waxes are composed of various types of hydrocarbons. Forexample, medium paraffin wax is composed primarily of straight chainhydrocarbons having carbon chain lengths ranging from about 20 to about40, with the remainder typically comprising isoalkanes and cycloalkanes.The melting point of medium paraffin wax is about 50° C. to about 65° C.Microcrystalline paraffin wax is composed of branched and cyclichydrocarbons having carbon chain lengths of about 30 to about 100 andthe melting point of the wax is about 75° C. to about 85° C. Furtherdescriptions of the petroleum wax that may be used in the invention maybe found in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rdEdition, Volume 24, pages 473-76, which is hereby incorporated byreference.

The vegetable lipid-based composition may contain up to about 49% byweight of the petroleum wax but preferably contains up to about 45%, upto about 35%, up to about 25% and more preferably up to about 17% byweight of the petroleum wax with the remainder being the vegetable lipidcomponent. For example, the vegetable lipid-based composition maycontain up to about 17% by weight medium paraffin wax. In general,superior candle quality is achieved when the vegetable lipid-basedcomposition contains a greater concentration of the vegetable lipidcomponent than the petroleum wax component. Moreover, even though avegetable lipid-based composition including up to about 49% by weight ofa petroleum wax will function as a suitable candle, superior candlequality may be achieved when the petroleum wax component is minimized.It is preferred that the vegetable lipid-based composition includes atleast about 3% by weight of the petroleum wax component.

In a preferred embodiment, the vegetable lipid-based composition onlyincludes the vegetable lipid component and petroleum wax. However,various odorants or colorants may be added to the vegetable lipid-basedcomposition as desired. U.S. Pat. No. 4,608,011, issued to Comstock onAug. 26, 1986, lists several odorants and colorants which may preferablybe added to the vegetable lipid-based composition and is herebyincorporated by reference in its entirety. Furthermore, colorstabilizing additives, such as ultraviolet light absorbing materials,may be added to prevent pigment color fading.

The vegetable lipid-based composition of the present invention may alsoinclude a very low level of an antioxidant, such as about 1 ppm to about10 ppm of t-butylhydroquinone (TBHQ) or butylated hydroxytoluene (BHT),to increase shelf life. Sodium ethylenediaminetetraacetic acid may beused in synergistic combination with the TBHQ and/or BHT for metalchelation.

The present invention also provides a candle formed from the vegetablelipid-based composition. The candle can be of any size and shapedesired. The candle preferably includes a wick which typically extendslongitudinally from one end of the candle to the other end. The wick ispreferably made from woven cotton or any other suitable material asknown in the art. The candle is preferably placed in a candle holderwhich is preferably composed of glass or any heat resistant material.

The candles formed from the vegetable lipid-based compositions of thepresent invention have superior solids content/mechanical stability ascompared to commercial paraffin candles at elevated temperatures. Forexample, when paraffin candles and the vegetable lipid-based candles ofthe present invention are stored overnight at 55° C., the paraffincandles liquify whereas the vegetable lipid-based candles remain solid(as determined by their ability to support a 4 gram marble on theirsurface). Although the vegetable lipid-based candles begin to softenwhen stored at 59° C., the candles remain solid. Furthermore, soot andsmoke formation was subjectively judged to be lower when candlesincluding a vegetable lipid-based composition were burned compared toparaffin wax-based candles under the same conditions. Additionally,combustion tests described in Example 6 show that candles including avegetable lipid-based composition of the present invention burnapproximately 80% longer than paraffin wax-based candles under identicalconditions. Therefore, a candle including a vegetable lipid-basedcomposition will last significantly longer than a paraffin wax-basedcandle.

The crystallization/solidification behavior of the vegetable lipid-basedcomposition of the present invention is significantly different than thebehavior of petrochemical products. It is therefore necessary to employrelatively slow process cooling rates in order to obtain smooth candleswith no visible crystal formation.

Reference will now be made to specific examples using the compositionsand processes above described. All percentages are by weight. It is tobe understood that the examples are provided to more completely describepreferred embodiments and that no limitation to the scope of theinvention is intended thereby. The following preparatory steps wereemployed in the Examples.

The components of the candle were weighed and combined in a clean glasscontainer. The composite material was obtained by heating to melt allsolid components to a liquid state with sufficient stirring to uniformlymix all components. The temperature range for melting was normallybetween approximately 75° C. to about 110° C. Although they are notnecessary for the mixing process, higher temperatures may be used.Temperatures in excess of 130° C. are to be avoided to minimizedegradation of the materials.

After the components were mixed, the composite material was eitherdirectly poured into product containers or was allowed to cool at roomtemperature to approximately 85° C. before being poured into productcontainers. A wick was normally added at this point, while the materialis still in the liquid state. The product was then cooled by standing atambient temperature (room temperature), by the use of air convection(fan) or by the use of a temperature controlled water bath in atemperature range of about 5° C. to about 50° C. Colder temperatures mayalso be used if faster cooling is desired. Although several differentcooling processes may be used, superior candles were made by minimizingthe pouring temperature and cooling rapidly using air convection or awater bath.

EXAMPLE 1

A 100% triglyceride lipid candle was prepared in accordance with thedescribed protocol. The fatty acid components of the triglyceride were13.7% palmitic acid, 74.2% stearic acid and 12.1% oleic acid.

EXAMPLE 2

A candle having 96% triglycerides and 4% microcrystalline wax wasprepared in accordance with the described protocol. The fatty acidcomponents of the triglyceride were 22.4% palmitic acid, 45.7% stearicacid, 28.9% oleic acid and 3.9% by weight linoleic acid.

EXAMPLE 3

A candle containing an 83% by weight fatty acid/triglyceride mixture and17% by weight microcrystalline paraffin wax was prepared in accordancewith the described protocol. Microcrystalline paraffin wax with amelting point of 79° C. and containing branched and cyclic hydrocarbonsof carbon chain length of about 30 to about 100 was added to a fattyacid/triglyceride mixture having 6% free fatty acids and 94%triglyceride wherein the free fatty acid component was stearic acid. Thefatty acid components of the triglyceride were 29.0% palmitic acid,68.8% stearic acid and 2.1% by weight oleic acid.

EXAMPLE 4

A candle containing 96% triglycerides and 4% medium paraffin wax wasprepared in accordance with the described protocol. Medium paraffin waxwith a melting point of about 65° C. and containing predominantlystraight chain hydrocarbons of carbon chain length of about 22 to about36 was added to a triglyceride having the following fatty acidcomponents: 18.0% palmitic acid, 35.2% stearic acid and 46.8% by weightoleic acid.

EXAMPLE 5

In another example, a vegetable lipid-based candle is made following theprotocol described above wherein the vegetable lipid-based compositionof the candle includes only a vegetable lipid and a petroleum wax.Specifically, the composition includes about 51% by weight to about 100%by weight of the fatty acid/triglyceride mixture and up to about 49% byweight of the petroleum wax component. The petroleum wax component isoptionally a medium paraffin wax, a microcrystalline paraffin wax or apetroleum wax obtained from crude oil refined to other degrees. Thefatty acid/triglyceride mixture can include about 1% by weight to about99% by weight of the free fatty acid and about 1% by weight to about 99%by weight of the triglyceride. The fatty acid components of thetriglyceride and the maximum respective percentages by weight that theymay be found in the triglyceride may be those detailed in Table 1. Thefree fatty acids present in the fatty acid/triglyceride mixture can be,for example, palmitic, stearic, behenic, arachidic, oleic or linoleicacid or any combination thereof. Other saturated or unsaturated freefatty acids may be included as the sole free fatty acids or incombination with other free fatty acids as long as the candle will be asolid at the temperature at which it is used. In other examples, thecomposition may include other components, such as colorants or odorants.

EXAMPLE 6

Combustion tests were performed to compare the vegetable lipid-basedcandles of the present invention with commercial paraffin candles. Anelectronic scale was placed on a table and a 4-wall baffle (10″×10″×10″)(25.4 cm×25.4 cm×25.4 cm) with the top and bottom surface open wassuspended 3.5 in (8.9 cm) above the table surface to allow free accessfor airflow below and above. The purpose of the baffle was to minimizeuncontrolled drafts and air convection. The electronic scale waspositioned in the baffle area at a distance from the base of the baffleof approximately one-third the baffle height. Candles of the followingcomposition were placed on the scale: paraffin candles composed of 150 gof 100% medium paraffin wax and vegetable lipid-based candles containing4% microcrystalline paraffin wax and 96% triglycerides having thefollowing fatty acid components: 22.4% palmitic acid, 45.7% stearicacid, 28.9% oleic acid and 3.9% by weight linoleic acid. The experimentwas run in duplicate for each candle composition. All candles hadidentical wicks and were present in identical containers.

The candles were burned for two hours and the mass loss rate wasrecorded. No significant variations in air composition or temperatureoccurred during the test period as the room was well-ventilated. Themeasured mass loss rates for the paraffin candles were 7.13 g/hour and7.08 g/hour. The measured mass loss rates for the vegetable lipid-basedcandles were 3.72 g/hour and 4.10 g/hour. Therefore, the vegetablelipid-based candles will burn approximately 80% longer than commercialparaffin candles.

While the invention has been illustrated and described in detail in theforegoing description, the same is to be construed as illustrative andnot restrictive in character, it being understood that only thepreferred embodiment has been shown and described and that all changesand modifications that come within the spirit of the invention aredesired to be protected.

1. A combustible candle, comprising: a plant derived compositionincluding triglycerides obtained from oils selected from the groupconsisting of soybean, corn, and palm oils, the triglycerides consistingessentially of fatty acid components having up to 2 double bonds and 16or 18 carbon atoms; at least one petroleum wax; and the candle includinga greater amount of the plant derived composition than the at least onepetroleum wax.
 2. The candle of claim 1, wherein the fatty acidcomponents include stearic, palmitic and oleic acid.
 3. The candle ofclaim 2, wherein the fatty acid components consist essentially ofpalmitic, stearic and oleic acid.
 4. The candle of claim 2, wherein thestearic acid comprises up to about 74% by weight of the triglycerides,the palmitic acid comprises up to about 39% by weight of thetriglycerides, and the oleic acid comprises up to about 73% of thetriglycerides.
 5. The candle of claim 1, wherein the triglycerides areobtained from hydrogenated soybean oil.
 6. The candle of claim 1,wherein the triglycerides consist essentially of fatty acid componentshaving up to 1 double bond.
 7. A candle comprising petroleum wax and atleast about 51% by weight of a vegetable-based composition, thevegetable-based composition including triglycerides obtained from oilsselected from the group consisting of soybean, cottonseed, corn,sunflower, canola and palm oils, the triglycerides consistingessentially of fatty acid components having up to 2 double bonds, thefatty acid components including stearic, palmitic and oleic acids. 8.The candle of claim 7, wherein the fatty acid components have 16 or 18carbon atoms.
 9. The candle of claim 7, wherein the stearic acidcomprises up to about 74% by weight of the triglycerides, the palmiticacid comprises up to about 39% by weight of the triglycerides, and theoleic acid comprises up to about 73% of the triglycerides.
 10. Thecandle of claim 9, wherein the fatty acid components consist essentiallyof stearic, palmitic and oleic acid.
 11. The candle of claim 7, whereinthe triglycerides are obtained from oils selected from the groupconsisting of soybean, corn and palm oils.
 12. The candle of claim 7,wherein the combustible candle composition is solid at a temperature ofup to 55° C.
 13. The candle of claim 7, wherein the fatty acidcomponents of the triglycerides comprise up to 3.9% by weight of fattyacids having 2 double bonds.
 14. A candle, comprising: a petroleum wax;plant derived triglycerides having fatty acid components consistingessentially of fatty acid components with 16 or 18 carbon atoms, thefatty acid components including stearic, palmitic and oleic acid; andthe candle including a greater amount of the plant derived triglyceridesthan the petroleum wax.
 15. The candle of claim 14, wherein the fattyacid components have up to 2 double bonds.
 16. The candle of claim 15,wherein the fatty acid components of the triglycerides comprise up to3.9% by weight of fatty acids having 2 double bonds.
 17. The candle ofclaim 15, wherein the fatty acid components have up to 1 double bond.18. The candle of claim 14, wherein the fatty acid components consistessentially of palmitic, stearic and oleic acid.
 19. The candle of claim14, wherein the stearic acid comprises up to about 74% by weight of thetriglycerides, the palmitic acid comprises up to about 39% by weight ofthe triglycerides, and the oleic acid comprises up to about 73% byweight of the triglycerides.
 20. The candle of claim 14, wherein thecombustible candle composition is solid at a temperature of up to 55° C.21. A candle, comprising: petroleum wax; a plant derived compositionhaving triglycerides consisting essentially of 3 different fatty acidcomponents; and wherein the composition includes a greater amount of theplant derived composition than the petroleum wax.
 22. The candle ofclaim 21, wherein the fatty acid components have up to 2 double bonds.23. The candle of claim 21, wherein the fatty acid components have 16 or18 carbon atoms.
 24. The candle of claim 21, wherein the fatty acidcomponents are stearic, palmitic and oleic acid, the stearic acidcomprising up to about 74% by weight of the triglycerides, the palmiticacid comprising up to about 39% by weight of the triglycerides, and theoleic acid comprising up to about 73% of the triglycerides.
 25. Thecandle of claim 21, wherein the fatty components have up to 2 doublebonds.
 26. The candle of claim 25, wherein the fatty acid components ofthe triglycerides comprise up to 3.9% by weight of fatty acids having 2double bonds.
 27. The candle of claim 21, wherein the fatty acidcomponents have up to 1 double bond.